Irish actor Allen Leech revealed that Lady Mary Crawley will move into a central role in season four of the hit series “Downton Abbey.”

Leech, who plays Tom Branson on the show, said that his character will be involved in some plot twists during the next season. The Star reported he said, “There are a couple of things I can’t really talk about. But yeah, definitely toward the middle of the series it gets very exciting.”

The fourth season jumps ahead six months since the finale of season three. One of the first scenes centres around the grave of Matthew Crawley who died in a car accident in the final minutes of last season. Leech said that Lady Mary Crawley, played by Michelle Dockery, will come to terms with Matthew’s death. He said, “She’s trying to get over the death of her husband and that’s a very central arc to it.”

Leech also said about the upcoming season, “Downton is in a period of change, as it always is, and that’s pretty integral again to the family trying to cope with the changes that come with the 20s.”

Some new cast members will join the show in the fourth season. Jazz musician Jack Ross, who sings at an exclusive club, will be the first black character on the show. Tom Cullen will play Lord Gillingham, a family friend of the Crawleys who will visit Downton during a party. Nigel Harman will also join the cast as Green, a valet. Dame Harriet Walter will play the Dowager Countess’, played by Maggie Smith, old friend Lady Shackleton. Joanne Davis will play the guest role of the Duchess of Yeovil. Julian Ovenden will play aristocrat Charles Blake and Dame Kiri Te Kanawa will play a house guest. Shirley MacLaine will star in the season finale.

Executive producer Gareth Neame said in a statement quoted by the Huffington Post, “‘Downton Abbey’ has seen many great characters visit the house over the years and we couldn’t be more thrilled to welcome the new faces that will be joining the regular cast of ‘Downton Abbey’ in season four.”

Filming for the new season began this week in Oxfordshire, England. The season will screen in the autumn of 2013 in the UK and in the spring of 2014 in the U.S.